Search Results (206)

The high salt concentration in kitchen waste (KW) can impede the performance of subsequent biological treatment. However, the impact of salt stress on the quality of vermicomposting products generated from KW remains unclear. In this study, the effects of high salt concentration in KW on earthworm function and vermicompost quality were investigated by comparing two groups: a 1.5% salt (ST) group and a control (CK) group without salt. Results showed a significant decrease in the number and weight of earthworms in the ST (p < 0.01), with a mortality rate of 24.33% (p < 0.05) after vermicomposting. Compared to the CK, ST treatment resulted in a significant increase in catalase activity and a significant decrease in superoxide dismutase activity (p < 0.01). In addition, mucus secretion by earthworms decreased by 82.6% in ST (p < 0.01). Moreover, salt stress reduced KW humification during vermicomposting, lowering the humification index and β:α index by 23.7% and 41.2%, respectively. Microbial composition shifted under spatially heterogeneous selection pressures, leading to a 37.5% decrease in Ascomycota abundance, a 58.3% increase in Bacteroidetes abundance, and a 72.3% reduction in Proteobacteria abundance. Furthermore, the vertical stratification of physicochemical conditions significantly affected both microbial abundance and earthworm biomass in the ST treatment (p < 0.01), suggesting a salt–microbe–earthworm interaction mechanism. This study reveals that salt stress disrupts humification by impairing key microbial functions and ecological roles of earthworms during vermicomposting of KW. Full article

Co-combustion in a refuse incinerator is a primary method for treating aged refuse (AR). Given the high contents of heavy metals and chlorine in AR, it is crucial to investigate their release and fate during co-combustion to achieve environmentally sound treatment. This study investigated the release and volatilization of heavy metals (Cd, Cr, Zn, Ni, Cu, Pb) and HCl during the co-combustion of AR and municipal solid waste (MSW) through chemical thermodynamic equilibrium analysis. The effects of several parameters on the volatilization of heavy metals and HCl were analyzed, including incineration temperature, the N₂/O₂ ratio, the degree of refuse classification, the blending ratio of AR, and the effects of conventional calcium-based additives. The results showed that high temperature promoted the volatilization of Cd, Pb, Cu, Ni, and HCl. A lower N₂/O₂ ratio suppressed Zn and HCl volatilization. A higher degree of MSW classification (with lower proportions of kitchen and wood waste) and an increased AR blending ratio enhanced Zn fixation. CaO at high temperature only suppressed HCl volatilization, with a minor effect on heavy metals. Two modified calcium-based additives (CaBSiO₄OH and CaB₅SiO₉(OH)₅) with strong high-temperature Cu removal capabilities were explored, and their risk index was analyzed. Full article

Given the sustainable increase in kitchen waste production, the treatment of organic waste is quite important for both alleviating environmental risks and recovering biomass energy. Anaerobic digestion (AD) could achieve the goals of both organic stabilization and the green energy production of biogas. However, AD conducted at a high organic loading rate can easily suffer from low treatment efficiency due to the accumulation of volatile fatty acids and an imbalance in the microbial community. This study investigated the functional microbial enhancement strategy for enhancing AD performance. The results suggested that adding 10 g of granular sludge every 5 days could enhance AD efficiency. In that case, the daily average methane production rate was increased by 43.21% compared to that in the control group, and the pH and ammonia nitrogen concentration were maintained at the optimal level. Humic acid production was strengthened; it served as an electron shuttle, which facilitated direct interspecies electron transfer. Both Cloacimonadota and Methanobacterium were enriched in the system inoculated with the granular sludge. Metabolomics indicated that the acetyl–CoA conversion was strengthened, and that energy metabolism (complex I and archaeal ATPase) was also enhanced. The granular sludge inoculation also activated the archaeal genetic information processing system. This technology could promote the generation of green energy, which is more conducive to sustainable resource development. This study provides the theoretical basis for a microbial enhancement strategy that can enhance kitchen waste AD. Full article

Kitchen waste management strongly affects greenhouse gas (GHG) emissions, especially in small municipalities with limited treatment options. This study assessed alternative strategies for Aya Town, Japan, by integrating life cycle assessment (LCA) with Geographical Information System (GIS)-based transport analysis. Six scenarios were designed, ranging from mandatory composting with frequent collection to full incineration at a regional waste-to-energy (WtE) facility. Emissions were estimated from transport, composting, and incineration processes, with sensitivity tests on composting electricity use (20, 50, and 90 kWh per ton) and WtE efficiency (15%, 17.9%, 20%, and 25%). The results showed that reducing collection frequency lowered emissions by about 9% relative to the current system, while decreasing composting participation further reduced emissions. Full incineration yielded the lowest emissions, whereas sensitivity analyses confirmed that facility parameters influenced absolute values but not the relative ranking of scenarios. These findings emphasize the importance of transport logistics, participation rates, and infrastructural context. High-quality compost may justify limited voluntary composting; however, WtE incineration remains the most robust option for climate mitigation in Japan’s incineration-based waste management system. Full article

This study presents an innovative approach to the production of hydrogen from liquids following hydrothermal treatment of biowaste, offering a potential solution for renewable energy generation and waste management. By combining biological and hydrothermal processes, the efficiency of H₂ production can be significantly improved, contributing to a reduced carbon footprint and lower reliance on fossil fuels. The inoculum used was fermented sludge from a wastewater treatment plant, which had been thermally pretreated to enhance microbial activity towards hydrogen production. Kitchen waste, consisting mainly of plant-derived materials (vegetable matter), was used as a substrate. The process was conducted in batch 1-L bioreactors. The results showed that higher pretreatment temperatures (up to 180 °C) increased the hydrolysis of compounds and enhanced H₂ production. However, temperatures above 180 °C resulted in the formation of toxic compounds, such as catechol and hydroquinone, which inhibited H₂ production. The highest hydrogen production was achieved at 180 °C (approximately 66 mL H₂/g_TVSKW). The standard Gompertz model was applied to describe the process kinetics and demonstrated an excellent fit with the experimental data (R² = 0.99), confirming the model’s suitability for optimizing H₂ production. This work highlights the potential of combining hydrothermal and biological processes to contribute to the development of sustainable energy systems within the circular economy. Full article

Composting can be perceived as an art and science of converting organic waste into a rich and nutritious soil amendment—compost. The existing literature talks about how and what parameters need to be monitored in the process of composting and what actions are to be taken to optimize the process. In this paper, the development, deployment and data analytics of a compost monitoring system are presented, wherein not only the parameters to be measured but also the topology, mechanical design and battery operation details, which are crucial for the deployment of the system, are considered. Having realized that the temperature plays an important role in the process of composting, a contactless method of monitoring the compost temperature, using thermal imaging, has been investigated. Results showing the screenshots of the successfully developed system, plots of the obtained data and the inferences drawn from them are presented. This work not only contributes to the composting data, which is scarce, but also brings out the advantages of using thermal images in addition to temperature sensor probes. Full article

Black Soldier Fly Larvae Meal (BSFLM) has gained attention as a sustainable feed ingredient in aquaculture, yet its functional properties at the cellular level remain underexplored. This study evaluated the antioxidative and proliferative effects of BSFLM derived from larvae fed different waste-based substrates (Kitchen Waste (KW); Agricultural Waste (AW); Aquaculture Sludge (AS); Aquaculture Offal (AO); Mix (MX)), using the Atlantic salmon (Salmo salar) SHK-1 cell line as an in vitro model. BSFLM treatments were assessed through four assays: oxidative stress mitigation under H₂O₂ exposure, baseline cellular proliferation, proliferation under protein-standardized conditions, and recovery from serum starvation. Each assay was carried out in three independent experiments with three replicates per treatment, and changes in coloration were quantified using MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide). The results showed that BSFLM from plant-based substrates, particularly MX and KW diets, significantly (p < 0.05) improved cell viability across all assays. Under oxidative stress, MX (121.1% ± 5.9) and AW (119.9% ± 6.1) treatments maintained viability levels comparable to Vitamin C (119.3% ± 3.8) (250 ppm of DSM Stay-C) and the control (137.5% ± 11.6). In proliferation assays, MX (207.6% ± 16.3) and KW (196.3% ± 11.1) outperformed animal-based treatments AO (122.6% ± 4.4) and AS (113.1% ± 3.7), and these effects persisted under protein-standardized conditions, although the statistical significance was reduced. In the recovery from serum starvation assay, cells treated with MX (45.5% ± 1.9) and KW (42.0% ± 0.4) exhibited markedly higher viability than AS (15.5% ± 1.9) and AO (14.8% ± 2.2). The biochemical composition of BSFL reared on different substrates, including proximate, amino acid, fatty acid, and polyphenol profiles, was analyzed to contextualize the observed cellular responses. These findings highlight the superior functional properties of BSFLM derived from plant-based substrates and support its potential use as a targeted functional feed ingredient in aquaculture feed formulations. Full article

The continuous increase in urbanization and global population has led to the generation of a substantial amount of kitchen waste, posing severe environmental and disposal challenges. The utilization of kitchen waste as organic biomass for biochar production offers a promising, sustainable, and cost-effective solution. This review comprehensively analyzes the recent developments in the transformation of kitchen waste into biochar. Moreover, the current study involves various synthesis techniques, the physicochemical characteristics of biochar, and its applications in soil and water remediation. Afterwards, the experimental parameters and feedstock types are critically evaluated in terms of their key characteristics for biochar. Moreover, the current study highlights the effectiveness of kitchen waste-derived biochar (KWBC) in decomposing organic pollutants, heavy metals, and pharmaceutical pollutants from contaminated environments. Additionally, the mechanisms of adsorption, ion exchange, complexation, and redox interactions are thoroughly illustrated to evaluate the pollutant removal pathways. At the end of the study, experimental parameters such as pH, dosage, contact time, and initial pollutant concentration are discussed, which play the main role in enhancing the adsorption capacity of biochar. Finally, this review outlines current limitations and proposes future directions for optimizing biochar performance and promoting its large-scale application in sustainable environmental management. Full article

The challenge of food waste poses significant economic, environmental, and ethical concerns worldwide, with the hospitality sector being particularly affected. This study explores food waste prevention and management practices in five-star hotels in Serbia, focusing on the knowledge, attitudes, and resourcefulness of head chefs as key actors in implementing sustainable solutions. A qualitative exploratory design was applied, combining semi-structured interviews with eight head chefs and hotel managers, in-kitchen field observations, and food waste audits conducted in eight luxury hotels in Belgrade. The food waste hierarchy framework was used to assess how head chefs understand and act upon food waste issues. Findings reveal that while food waste policies vary across hotels, head chefs demonstrate varying levels of awareness and resourcefulness, often shaped by corporate policies, training, and personal experience. Despite limitations in policy enforcement, many head chefs apply practical strategies such as FIFO stock rotation, local sourcing, and creative reuse of ingredients. This study advances the theoretical understanding of food waste management in hospitality by linking practice theory with culinary knowledge and corporate influence. It also provides practical implications for training, policy development, and sustainable hospitality operations in transitional economies. Full article

Municipal solid waste (MSW) management is identified as a significant sustainability concern. Source segregation (SS) is the most effective method of managing MSW, and anaerobic digestion (AD) is the most efficient treatment method. The aim of this study was to analyze the impact of waste collection rules on the efficiency and performance of AD. The potential biomethane yields for SS-kitchen waste and SS-biowaste were calculated, determined in laboratory tests, and verified full-scale. The content of the organic fraction in SS-biowaste reached about 81 to 86%; however, regarding SS-kitchen waste, it reached almost 92%. The primary contaminants were plastics. The obtained biogas yield was slightly higher for SS-kitchen waste (136.2 m³/ton), compared to SS-biowaste (116.6 m³/ton). The pH values, acidity, and alkalinity indicated no risk of exploitation using both feedstocks. However, in the case of SS-kitchen waste, the acetic acid content was about 2.5 times higher than that of SS-biowaste. Furthermore, the acetic acid was noted in the outlet section (about 140–160 mg/kg), indicating no complete organic matter decomposition. Regarding SS-kitchen waste, the calculated methane yield reached 137.1 m³_CH4/ton and laboratory tests showed a methanogenic potential of 129.7 m³_CH4/ton, while at full-scale, it reached about 82.2 m³_CH4/ton. The research confirmed that the SS of biowaste positively impacts MSW management by improving waste composition and increasing recycling possibilities. AD is an effective biowaste treatment process, allowing energy recovery from waste. Full article

In this study, we optimize the kitchen waste fermentation process by adjusting the fermentation time and temperature to prepare high-efficiency carbon sources to enhance nitrogen and phosphorus removal during sewage treatment. Simulated kitchen waste fermentation experiments were performed, and the impact on the pollutant removal efficiencies was analyzed using a sequence batch reactor (SBR). The results showed that the volatile fatty acid (VFA) concentration peak occurred on the first day of fermentation, the maximum increment was 543.19 mg/L, and the maximum soluble chemical oxygen demand/total nitrogen (COD/TN) ratio was 40.49. However, the highest total nitrogen (TN) removal efficiency was 70.42% on the second day of fermentation. An increase in temperature promoted organic matter release, with the highest soluble COD concentration of 22.69 g/L observed at 45 °C. Further, the maximum VFAs production (935.08–985.13 mg/L) occurred from 25 to 35 °C. In addition, the fermentation products in this temperature range also showed the optimal removal efficiencies for total phosphorus (TP) and TN at 91.50% and 79.63%, respectively. Although 15 °C and 45 °C were beneficial for COD reduction, they were not conducive to nitrogen and phosphorus removal. The energy consumption and the synergistic pollutant removal showed that the optimal fermentation conditions were 2 days at 35 °C. Under these conditions, the kitchen waste-derived carbon source achieved efficient TN and TP removal, as well as COD reduction. Therefore, these conditions provide a feasible solution for the “reduction and sustainability” of kitchen waste. Full article

With the rapid expansion of urban green spaces and the increasing amount of domestic waste, efficient and sustainable treatment of green waste (GW) and kitchen waste (KW) has become a pressing issue. Co-composting offers a green and low-carbon solution, yet a systematic understanding of its greenhouse gas (GHG) emission dynamics remains lacking. This study aims to investigate the impact of varying GW:KW ratios on GHG emissions during composting, in order to identify optimal mixing strategies and sup-port the development of low-carbon urban waste management systems. Six treatments with different GW:KW ratios (10:0, 9:1, 8:2, 7:3, 6:4, and 5:5) were evaluated under continuous aeration for 42 days. Results showed: (1) All treatments exhibited a typical composting temperature profile (mesophilic, thermophilic, cooling, maturation), with final seed germination index (GI) > 95% and significantly reduced E4/E6 ratios, indicating maturity. (2) When kitchen waste (KW) was ≤20%, cumulative GHG emissions slightly increased; KW ≥ 30% led to net reductions, with the 6:4 treatment (A4) achieving the highest decrease (17.44%) in total CO₂-equivalent emissions. In conclusion, maintaining KW at 40–50% optimally balances compost maturity and emission reduction, providing a viable strategy for the high-value utilization of urban organic waste and carbon mitigation. Full article

In recent years, there have been significant advances in the application of technology in professional kitchens. This evolution of “smart kitchens” has transformed the food processing sector, ensuring higher standards of food safety through continual microbial monitoring, quality control, and hygiene improvements. This review critically discusses the recent developments in technology in commercial kitchens, focusing on their impact on microbial safety, operational efficiency, and sustainability. The literature was sourced from peer-reviewed journals, industry publications, and regulatory documents published between 2000 and 2025, selected for their relevance to the assurance of food safety using emerging technologies especially for use in commercial kitchens. Some of the most significant of these technologies currently being employed in smart kitchens include the following: smart sensors and IoT devices, artificial intelligence and machine learning systems, blockchain-based traceability technology, robotics and automation, and wearable monitoring devices. The review evaluated these technologies against criteria such as adherence to existing food safety regulations, ease of integration, cost factors, staff training requirements, and consumer perception. It is shown that these innovations will significantly enhance hygiene control, reduce the levels of waste, and increase business revenue. However, they are constrained by high installation costs, integration complexity, lack of standardized assessment measures, and the need for harmonizing automation with human oversight. Thus, for the widespread and effective uptake of these technologies, there is a need for better collaboration between policymakers, food experts, and technology innovators in creating scalable, affordable, and regulation-compliant solutions. Overall, this review provides a consolidated evidence base and practical insights for stakeholders seeking to implement advanced microbial safety technologies in professional kitchens, highlighting both current capabilities and future research opportunities. Full article

Given the increasing volume of selectively collected bio-waste and the requirement to increase waste treatment system energy efficiency, dry anaerobic digestion (DAD) represents a more sustainable choice for the treatment of municipal organic fraction instead of conventional technologies. The current paper provides an overview of the existing knowledge on DAD of green waste or kitchen waste collected selectively. Key substrates characteristics (chemical composition, methane potential), novel reactor design and process conditions relevant to effective digestion at elevated dry matter content are considered. Of special interest is the process intensification techniques, impact of contamination and co-fermentation opportunity with other biodegradable wastes. This article also discusses energy and economic performance of DAD plants and puts their environmental burden in perspective versus other bio-waste treatment processes. The current legislation and DAD’s role in the circular economy are also considered. Selectively collected biowaste has significant energy potential and dry anaerobic digestion is an effective technology, especially in areas with limited water availability, offering both waste volume reduction and minimized energy losses. The aim of this work is to introduce the potential of this technology as a sustainable option within the context of renewable energy and modern waste management. Full article

Determining the amount of biowaste generated, separated, and recycled at source in households (BHrecycled) is crucial for assessing its potential inclusion in the total mass of waste prepared for reuse and recycling on the country level. Although the EU has introduced standardized rules for BHrecycled measurement, it is still a major challenge. This study, the first to be conducted on a large scale in Poland and the EU countries, aimed to determine the actual mass of BHrecycled (kitchen waste (B_K) per capita per year (kg/(capita·year)) and garden waste (B_G) per square meter of green area (kg/(m²·year)) in 1150 households that use an active composting unit located in more than 400 municipalities in all the voivodeships in Poland. Each municipality is characterized by individual MSW generation (MSW_G) values (the amount of waste generated per capita per year). The MSW_G values of the municipality where the household was located were used to group the data of B_K and B_G. In Poland, the average masses of B_K and B_G remained within the ranges of 81.02–107.49 kg/(capita·year) and 1.02–2.87 kg/(m²·year), respectively, across the MSW_G value. However, there was no clear statistical relationship between the MSW_G value and B_K or B_G. The average masses of B_K and B_G were ca. 97 kg/(capita·year) and ca. 2 kg/(m²·year). These results enable the determination of the total amount of BHrecycled in Poland. By incorporating these findings into waste management, strategies, monitoring, and reporting practices can be improved. Moreover, it promotes compliance with the EU recycling targets. Full article